An optical proximity sensor often emits light, and detects the photons in the returned light signal. Because light can be reflected and scattered by cover glass and ink layer printed on the cover glass, optical crosstalk is a concern for the optical proximity sensors. In one embodiment, the present disclosure provides an optical proximity sensor including a linear polarizer to cover the photo detector, or a polarizer to cover the light emitting device, or two polarizers to cover both the photo detector and the light emitting device. The polarizer blocks the s-polarized light and only allows the p-polarized light to pass through. Because the scattered light is predominated by the s-polarization, the optical crosstalk may be reduced.